JP2001006304A - Magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for reducing power consumption at the time of seeking without slowing an access time to a specified sector when a request for accessing to the specified sector is generated, in the moving speed control of a magnetic head of the magnetic disk device. SOLUTION: When a magnetic head is moved to a target sector, the present position of the magnetic head 1 is obtained from the information on the head position of the magnetic head 1 from a head position detecting part 4. A time firstly accessible to the target sector is calculated beforehand from the physical position information on the target sector and the present position information on the head 1, as well as head structure driving capability of the disk device. The moving speed of the head and the acceleration-deceleration pattern are decided so that the seek operation to the track, where the target sector exists, is completed spending that time, and the motion of the head structure driving part 3 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of a moving speed of a magnetic head of a magnetic disk drive, and when a request for access to a specified sector occurs, without reducing the access time to the specified sector. And a means for reducing power consumption at the time of seeking.

[0002]

2. Description of the Related Art In a conventional magnetic disk drive, when a request to read or write an arbitrary sector on a disk occurs,
The magnetic head is moved from the current position to the track where the target sector is located in the shortest time, and when the target sector reaches a position accessible by the magnetic head by rotation of the magnetic disk, information in the sector is read / written.

That is, in the conventional magnetic disk drive, in any case, in order to move the magnetic head to the track where the target sector exists in the shortest time, the seek operation to the track where the target sector exists is completed. From
A waiting time occurs until the target sector reaches a position accessible by the magnetic head.

On the other hand, in order to reduce such a waiting time, a method of arranging a head sector of a track at a position in consideration of a seek time from a continuous preceding track is used. Although the latency for sequential access of sectors is reduced, the latency for random access has not been improved.

In the magnetic disk drive, when reading or writing an arbitrary sector on the disk, a data read / write circuit required for reading / writing the sector must be activated. There is a method that activates only the data read / write circuit. In a magnetic disk drive having this method, a data read / write circuit is started at a specific timing such as before or after a seek operation to a track where a target sector is present, during a seek operation, or immediately before reading or writing of a sector.
The data read / write circuit is stopped at the end of data read / write to reduce power consumption.

[0006]

As described above, in the conventional magnetic disk drive, all target sectors cannot be accessed until the target sector reaches a position accessible by the magnetic head. In response to a media access request, the magnetic head is moved to the track where the target sector exists in the shortest time. In order to move the magnetic head to the track where the target sector exists in the shortest time, a force is required to move the head structure at the maximum speed, and each time a large current is applied to the head structure drive circuit. Become. Therefore, the power consumption during the seek increases, which hinders a reduction in power consumption.

A data read / write circuit necessary for reading / writing a sector requires a stabilization time until the circuit can be used normally. Therefore, unlike the related art, the seek time to the track where the target sector exists, the time until the target sector reaches a position accessible by the magnetic head after the seek operation is completed, or the stabilization time of the data read / write circuit are not considered. In the case of a control method in which the data read / write circuit is started at a specific timing, the target sector reaches a position accessible by the magnetic head depending on the position of the target sector after the seek operation is completed and the start timing of the data read / write circuit. Despite that, the data read / write circuit is not in a usable state, causing a rotation wait, and the time during which the data read / write circuit is activated may be longer than necessary, resulting in lower power consumption. It is hindering.

[0008]

In order to solve the above-mentioned problems, a magnetic disk drive according to the present invention, when moving a magnetic head to a target sector, uses the head position information of the magnetic head 1 from a head position detector 4. Find the current position of the head,
From the physical position information of the target sector, the current position information of the head, and the head structure drive capability of the magnetic disk drive, a time at which the target sector can be accessed first is calculated in advance, and the time required for the target sector is calculated. A magnetic head device comprising: determining a moving speed and an acceleration / deceleration pattern of a head so as to complete a seek operation to an existing track; and controlling an operation of a head structure driving unit. The sector arrival time is defined as the time required from the moment the magnetic head starts moving to the track where the target sector exists to the time the target sector first reaches a position accessible by the magnetic head by rotation of the magnetic disk,
When a time obtained by adding a rotation waiting time obtained by multiplying the rotation time of the magnetic disk by an integer n equal to or more than 0 to the sector arrival time is set as a target sector accessible time, the target sector accessible time is obtained. Determine the minimum integer n that satisfies the relationship ≧ (the shortest time required to move the magnetic head to the track where the target sector is located at the earliest), and substitute the n into the target sector accessible time obtained. A magnetic disk drive characterized in that a moving speed and an acceleration / deceleration pattern are determined and a magnetic head is moved so as to complete head movement and head positioning to a track in which a target sector is present. According to this, a magnetic disk that reduces power consumption during seek without reducing access time compared to the conventional method. It is possible to provide a click system.

In order to solve the above-mentioned problems, the magnetic disk drive of the present invention substitutes the determined integer n from the moment when the magnetic head starts moving to the track where the target sector exists. When a time obtained by subtracting the stabilization time required for stabilizing the data read / write circuit from the obtained target sector accessible time elapses, the data read / write circuit is activated, and the data read / write circuit is activated at the end of the read / write of necessary data. 3. The magnetic disk drive according to claim 2, wherein the operation time of the data read / write circuit is controlled by stopping the operation, and the operation efficiency of the data read / write circuit is optimized according to this configuration.
It is possible to provide a magnetic disk drive that reduces power consumption during reading and writing.

[0010]

(Embodiment 1) Embodiments of the present invention described in claims 1 and 2 of the present invention will be described below with reference to the block diagram of FIG. FIG.
FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, a media access management unit 7 receives a designated sector access command 18 from a host system 8, and receives information 19 indicating a track position where a target sector exists and a target sector. , The information 20 indicating the track position where the target sector exists, and the target sector arrival time calculating section 5 indicating the position of the target sector on the track. Information 20 is given.

The head position detector 4 reads head position information 15 from the magnetic disk 2 through the head structure 1 and calculates information 16 indicating the current track position and information 17 indicating the current position on the track. Information 16 indicating the current track position is stored in the shortest seek time calculation unit 6.
To the target sector arrival time calculation unit 5 with information 17 indicating the current position on the track.

The shortest seek time calculator 6 calculates the current seek position from the information 19 indicating the track position where the target sector exists, the information 16 indicating the current track position, and the predetermined head structure drive capability of the magnetic disk drive. Seek time 2 from the track of the target sector to the track where the target sector exists 2
2 is given to the target sector accessible time calculation unit 9.

The target sector arrival time calculation unit 5 can access the target sector based on information 20 indicating the position of the target sector on the track, information 17 indicating the current position on the track, and the rotation cycle of the magnetic disk 2. The time 21 until the first position is reached is obtained and given to the target sector accessible time calculation unit 9.

The target sector accessible time calculation unit 9 comprises:
Shortest seek time 2 to the track where the target sector exists 2
2, the time 21 until the target sector first reaches the accessible position, and the rotation cycle of the magnetic disk drive,
The minimum integer n of 0 or more that satisfies the relationship (time required for the target sector to first reach an accessible position + rotation cycle of magnetic disk device * n) ≧ (shortest seek time to the track where the target sector exists). And the target sector accessible time 23 obtained by substituting that time into (time until the target sector first reaches the accessible position + rotation cycle * n of the magnetic disk drive * n) is determined by the head structure driving. This is given to the control unit 12.

The head structure drive control unit 12 controls the moving speed and acceleration / deceleration of the head structure 1 so that the magnetic head requires the target sector accessible time 23 and completes the seek operation to the track where the target sector exists. Calculate the pattern,
From these values, the head structure drive current instruction value 24 is determined and supplied to the head structure drive circuit 13 to control the operation of the head structure drive unit 3.

Next, a description will be given with reference to the flowcharts of FIGS. FIG. 2 is a schematic flowchart of the entire process according to an embodiment of the present invention, and FIG. 3 is a flowchart of a head moving speed control process for a track where a target sector exists.

In FIG. 2, first, in a step S1, it is determined whether or not a media access command from a host system has been received. If not, step S1 is repeated until it is received. If received, step S2
To execute the head moving speed control process for the track where the target sector exists, which will be described with reference to FIG.

In FIG. 3, first, in step S11,
The contents of the received media access command are analyzed, and the track position where the target sector to be accessed exists and the position of the target sector on the track are calculated. Next step S1
In step 2, based on the current head position information from the head position detection unit 4, the track position where the head currently exists and the current position on the track are calculated.

In the next step S13, step S11
From the track position where the target sector is present, the track position where the head is present, and the head structure driving capability of the magnetic disk drive calculated in step S12, the shortest distance from the current track to the track where the target sector is present is calculated. Calculate the seek time. Next step S14
Then, calculated in step S11 and step S12,
From the position of the target sector on the track, the current position on the track, and the rotation period of the magnetic disk, the time until the target sector first reaches the accessible position is calculated.

In the next step S15, step S13
Using the value calculated in step S14 and (the time until the target sector first reaches the accessible position + the rotation period of the magnetic disk device * n) ≧ (the shortest seek time to the track where the target sector exists) That is, the minimum integer n equal to or greater than 0 that satisfies the relationship, that is, the number of times the target sector must pass through a position accessible by the magnetic head even if the head moves to the track where the target sector exists at the shortest speed. I do.

In the next step S16, the target sector access obtained by substituting n calculated in step S15 into (time until the target sector first reaches an accessible position + rotation cycle of magnetic disk drive * n) is obtained. Find available time.

Then, in step S17, step S
The head moving speed and the acceleration / deceleration pattern that complete the seek operation to the track where the target sector exists in the target sector accessible time calculated in step 16 are calculated, and the head structure drive current instruction is calculated from these values. The value is determined and given to the head structure drive circuit 13. This completes the head moving speed control process for the track where the target sector exists.

With such a configuration, in order to move the magnetic head at a moving speed or an acceleration / deceleration pattern that can access the target sector immediately after the completion of the seek operation, the current applied to the head structure drive circuit 13 is controlled by a conventional method. The power consumption during the seek can be reduced without reducing the access time as compared with the conventional method.

(Embodiment 2) An embodiment of the present invention described in claim 3 of the present invention will be described below with reference to the block diagram of FIG.

In FIG. 1, a target sector accessible time calculation unit 9 calculates a target sector accessible time 23 in accordance with a designated sector access command 18 from the host system 8 in the same procedure as in the first embodiment. Startup time management unit 1
Give to 0.

The activation time management section 10 subtracts the stabilization time required for stabilizing the data read / write circuit from the target sector accessible time 23 to obtain the data read / write circuit activation time. The start-up time management unit 10 has a circuit capable of measuring time therein, and when the start-up time of the data read / write circuit elapses, gives a data read / write circuit start-up command 26 to the data read / write circuit 11, and starts the start-up time of the data read / write circuit 11. Control.

Next, a description will be given with reference to the flowcharts of FIGS. FIG. 2 is a schematic flowchart of the entire process showing an embodiment of the present invention, and FIG. 4 is a flowchart of a data read / write circuit drive timing control process.

In FIG. 2, after the head moving speed control processing for the track where the target sector exists in step S2 is executed, the process proceeds to step S3, and the data read / write circuit drive timing control processing described in FIG. 4 is executed.

In FIG. 4, first, in step S21, the stabilization time of the data read / write circuit is subtracted from the target sector accessible time calculated in step S16 of the head moving speed control process for the track where the target sector exists in FIG. Then, a data read / write circuit activation time is obtained.

In the next step S22, it is determined whether or not the data read / write circuit activation time has elapsed. If the data read / write circuit activation time has not elapsed, step S22 is repeated until the time has elapsed. If the time has elapsed, the process proceeds to step S23, where the data read / write circuit 11
Is given a data read / write circuit start instruction. This completes the data read / write circuit drive timing control process, and FIG.
Go to step S4. In step S4, immediately before the access to the target sector becomes possible, the media access can be executed immediately when the stabilization time of the data read / write circuit elapses and the access to the target sector becomes possible. . This completes the media access processing for the media access request from the upper system,
It returns to step S1.

With such a configuration, the data read / write circuit is stabilized immediately before the target sector becomes accessible, so that the operation efficiency of the data read / write circuit is improved and the power consumption at the time of reading / writing is improved. Can be reduced.

[0032]

As described above, according to the magnetic disk drive of the present invention, the time until the target sector can be accessed for the first time is determined, and the time is required for the track on which the target sector exists. By completing the seek operation, the power consumption during the seek can be reduced without reducing the access time as compared with the conventional method.

Further, by using the time until the target sector can be accessed for the first time, the start-up time of the data read / write circuit is controlled so that the stabilization of the data read / write circuit is completed immediately before the access to the target sector. By optimizing the operation efficiency, power consumption at the time of reading and writing can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a magnetic disk drive according to an embodiment of the present invention;

FIG. 2 is a flowchart showing an outline of the entire processing of the magnetic disk device.

FIG. 3 is a flowchart of a head moving speed control process for a track where a target sector exists in the magnetic disk device.

FIG. 4 is a flowchart of drive timing control processing of a data read / write circuit in the magnetic disk device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Head structure 2 Magnetic disk 3 Head structure drive part 4 Head position detection part 5 Target sector arrival time calculation part 6 Shortest seek time calculation part 7 Media access management part 8 Host system 9 Target sector accessible time calculation part 10 Start-up time Management unit 11 Data read / write circuit 12 Head structure drive control unit 13 Head structure drive circuit 15 Head position information 16 Information indicating current track position 17 Information indicating current position on track 18 Designated sector access command 19 Target sector Information indicating the existing track position 20 Information indicating the position of the target sector on the track 21 Time until the target sector first reaches an accessible position 22 Shortest seek time to the track where the target sector exists 23 Target sector accessible Time 24 Head structure drive Connection 26 data write circuit start command flow readings 25 head structure driving circuit and the head structure drive unit

Claims (3)

[Claims] When moving a magnetic head to a target sector, a current position of the magnetic head is obtained from head position information of the magnetic head from a head position detecting unit, and physical position information of the target sector and a current position of the magnetic head are obtained. Based on the information and the head structure drive capability of the magnetic disk drive, a time during which the target sector can be accessed first is calculated in advance, and the time is required to complete the seek operation to the track where the target sector exists. A magnetic head device, wherein a head moving speed and an acceleration / deceleration pattern are determined to control the operation of the head structure driving unit. 2. The time required from the moment when the magnetic head starts moving to the track where the target sector exists to the time when the target sector first reaches a position accessible by the magnetic head by the rotation of the magnetic disk is the sector arrival time. age,
When a time obtained by adding a rotation waiting time obtained by multiplying the rotation time of the magnetic disk by an integer n equal to or more than 0 to the sector arrival time is set as a target sector accessible time, the target sector accessible time is obtained. The minimum integer n that satisfies the relationship of ≧ (the shortest time required to move the magnetic head to the track where the target sector exists first) is determined, and the target sector accessible time obtained by substituting n is determined. A magnetic disk drive wherein a moving speed and an acceleration / deceleration pattern are determined and a magnetic head is moved so that head movement and head positioning to a track in which a target sector exists are completed. 3. From the moment when the magnetic head starts moving to the track where the target sector exists, the data read / write circuit can be stabilized based on the target sector accessible time obtained by substituting the determined integer n. When the time obtained by reducing the required stabilization time elapses, the data read / write circuit is activated, and the data read / write circuit is stopped at the end of the required data read / write, thereby controlling the operation time of the data read / write circuit. 3. The magnetic disk drive according to claim 2, wherein: